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)(27,31)(28,29)(30,32)(33,34)(35,40)(36,39)(37,38)(1,3,5,4)(2,6,7,8)(10,12)(11,17)(16,20)(19,23)(25,27,30,35)(26,31,32,40)(28,38,34,36)(29,37,33,39)(1,2)(3,6)(4,8)(5,7)(10,12)(11,17)(16,20)(19,23)(26,32)(27,35)(28,34)(37,39) 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)(25,28,30,34)(26,33,32,29)(27,36,35,38)(31,37,40,39)(1,4,5,3)(2,6,7,8)(9,12,14,10)(11,18,17,15)(13,16,21,20)(19,22,23,24)(25,27)(26,31)(28,36)(29,39)(30,35)(32,40)(33,37)(34,38)(1,2)(3,6)(4,8)(5,7)(9,13,14,21)(10,16,12,20)(11,19,17,23)(15,22,18,24)(25,29,30,33)(26,34,32,28)(27,37,35,39)(31,36,40,38)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.