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