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