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