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