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