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