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