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