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