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