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