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