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