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