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)(11,23)(12,27)(13,18)(14,19)(15,32)(16,22)(17,33)(20,25)(21,29)(24,37)(26,36)(28,35)(30,38)(31,34)(39,40) involution — undirected(1,3,5,2)(4,7,8,6)(9,11)(10,18)(12,28)(13,14)(15,25)(16,31)(17,26)(19,23)(20,38)(21,35)(22,36)(24,30)(27,39)(29,40)(32,37)(33,34)(1,4,5,8)(2,6,3,7)(9,12)(10,19)(11,24)(13,25)(14,29)(15,16)(17,30)(18,34)(20,37)(21,38)(23,36)(26,40)(27,32)(28,31)(2,3)(6,7)(9,13,14,11)(10,20,19,37)(12,25,29,24)(15,28,30,40)(16,31,17,26)(18,32,23,38)(21,34,27,36)(22,39,33,35)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.