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