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