One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,21)(12,18)(13,15)(14,19)(16,20)(17,23)(22,24)(25,26,30,34)(27,35,38,31)(28,39,37,32)(29,33,36,40)(1,2)(3,8)(4,6)(5,7)(9,11)(10,17)(12,14)(13,22)(15,19)(16,23)(18,24)(20,21)(25,27)(26,31)(28,36)(29,37)(30,38)(32,40)(33,39)(34,35) involution — undirected(1,3,5,4)(2,6,7,8)(9,12,16,13)(10,18,20,15)(11,14,23,22)(17,24,21,19)(25,26)(27,31)(28,32)(29,33)(30,34)(35,38)(36,40)(37,39)(1,2)(3,6)(4,8)(5,7)(9,13,16,12)(10,18,20,15)(11,22,23,14)(17,24,21,19)(25,26)(27,35)(28,32)(29,40)(30,34)(31,38)(33,36)(37,39)(1,2)(3,6)(4,8)(5,7)(9,14,16,22)(10,19,20,24)(11,12,23,13)(15,21,18,17)(25,28)(26,32)(27,36)(29,38)(30,37)(31,40)(33,35)(34,39)(1,4,5,3)(2,6,7,8)(9,15,16,18)(10,13,20,12)(11,19,23,24)(14,17,22,21)(25,29,30,36)(26,33,34,40)(27,37,38,28)(31,39,35,32)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.