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