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