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