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