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