One vertex per element, one color per generator, with an edge from x to x·s.
(9,10,16,15)(11,20,22,17)(12,18,13,23)(14,19,21,24)(26,31)(27,36)(28,35)(38,39)(1,2)(3,8)(4,6)(5,7)(9,11)(10,17)(12,14)(13,21)(15,20)(16,22)(18,24)(19,23)(25,26)(27,32)(28,34)(29,35)(30,31)(33,36)(37,39)(38,40) involution — undirected(1,3,5,4)(2,6,7,8)(9,12,16,13)(10,18,15,23)(11,14,22,21)(17,24,20,19)(25,27)(26,32)(28,37)(29,38)(30,36)(31,33)(34,39)(35,40)(1,2)(3,6)(4,8)(5,7)(9,13,16,12)(10,18,15,23)(11,21,22,14)(17,24,20,19)(25,27)(26,33)(28,37)(29,39)(30,36)(31,32)(34,38)(35,40)(1,2)(3,6)(4,8)(5,7)(9,14,16,21)(10,19,15,24)(11,12,22,13)(17,23,20,18)(25,28)(26,34)(27,37)(29,31)(30,35)(32,39)(33,38)(36,40)(1,4,5,3)(2,6,7,8)(9,15,16,10)(11,20,22,17)(12,23,13,18)(14,19,21,24)(25,29,30,34)(26,35,31,28)(27,38,36,39)(32,40,33,37)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.