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