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