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