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