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)(11,17)(12,15)(13,16)(14,19)(18,23)(20,22)(21,24)(25,26,30,34)(27,36,38,31)(28,35,37,32)(29,33,39,40)(9,11,13,19)(10,14,16,17)(12,18,20,24)(15,21,22,23)(25,26)(27,29)(28,32)(30,34)(31,33)(35,37)(36,40)(38,39)(1,3,5,4)(2,6,7,8)(9,12,13,20)(10,15,16,22)(11,18,19,24)(14,21,17,23)(25,27,37,40,30,38,28,33)(26,31,32,39,34,36,35,29)(10,16)(14,17)(15,22)(21,23)(25,28,30,37)(26,32,34,35)(27,33,38,40)(29,31,39,36)(1,4,5,3)(2,6,7,8)(11,19)(14,17)(18,24)(21,23)(25,29,37,31,30,39,28,36)(26,33,32,27,34,40,35,38)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.