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