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