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