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