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