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