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