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