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