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