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