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