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