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